1. Field of the Invention
The present invention generally relates to a magnetic disk drive, and more particularly, to a magnetic disk included in the magnetic disk drive and a method of using such magnetic disk.
2. Description of Related Art
In the art disclosed in Japanese published application JP-A 11-16327, magnetic disk drive is prevented from getting affected by the temperature of the surroundings by providing a heat-insulating material. This prevents condensation in the magnetic disk drive. However, this prior art does not give any consideration to the effect caused by the temperature of the surroundings itself. And therefore it could not provide high reliability on magnetic recording and retrieving of data.
In the art disclosed in Japanese published application JP-A 9-245419, it merely cools down the temperature of a magnetic disk drive in case the temperature rises beyond a pre-fixed value, and does not give any consideration to operating the magnetic disk drive at low temperatures.
Magnetic disk drives, i.e., hard disk drives (HDDs), was used as external storage devices for general computers at the very beginning. Magnetic disk drives have been gradually applied to personal computers and laptops. Recently, magnetic disk drives have been widely applied to various usages including audio systems, video systems, car navigation systems, copying machines and such, and the severity of operating conditions has been enhanced accordingly.
For example, although the temperature of an environment in which personal computers are used is in the range of about 5 to 55° C., HDDs to be used for other purposes such as the ones provided for vehicles, must be guaranteed to function properly for a wide range of temperatures, such as −20 to 70° C.
The coercive force of a magnetic disk increases at low temperatures and hence the recording ability of the magnetic disk becomes insufficient if information is recorded by a conventional recording method. Such increase of the coercive force cannot be coped with, simply by increasing current supplied to the coil of the recording head. However, if the coercive force of a magnetic disk is reduced to use the magnetic disk in a low-temperature environment, demagnetization increases due to thermal demagnetization at high temperature, and it is possible that data recorded on the magnetic disk vanishes when the temperature of the surroundings rises. Thus, it is difficult to cope with both maintaining recording ability at low temperatures and maintaining record holding ability at high temperatures.
Accordingly, what is needed is a magnetic disk drives that is capable of reliable recording and retrieving abilities under a wide range of surrounding temperature.